The application proposes a specific substudy within the larger, NICHD Study of Early Child Care. The proposed research will examine the nature and sources of literacy and cognitive development during the middle childhood years. Utilizing a complex, multi-level, interactive framework adopted from ecological perspectives, the research will focus specifically on the independent and combined influences of child, family and schooling factors in shaping growth of cognitive and literacy skills from first to fifth grade. A unique feature of the proposed research is the effort to develop analytic and methodological strategies for capturing on-line the interplay of multiple sources of influence on cognitive outcomes. The concept of a developmental 'pathway' or 'trajectory' is elaborated and utilized as a framework for describing the intricate nature of developmental change and the forces shaping it over the early school years. In addition, the proposal seeks to utilize the pathway notion to illuminate three currently important topics in cognitive development: domain-specificity, stability and change and risk-resilience. In each case, it will be argued that charting developmental pathways over time will help to understand which cognitive and literacy skills develop and which do not as a function of schooling experiences (domain-specificity), which skills show relative stability over time (stability vs. change) from the early to later school years and how harmful or beneficial outcomes are produced by the complex interactions of risk and protective factors (risk-resilience). Overall, the proposed research will advance understanding and study of the nature and sources of cognitive and literacy growth during the elementary school years.